Processing facilities are often managed using process control systems. Example processing facilities include (but are not limited to) manufacturing plants, chemical plants, crude oil refineries, ore processing plants, and paper or pulp manufacturing and processing plants. Among other operations, process control systems typically manage the use of motors, valves, and other industrial equipment in the processing facilities.
In conventional process control systems, process controllers are often used to control the operation of the industrial equipment in the processing facilities. The process controllers could, for example, monitor the operation of the industrial equipment, provide control signals to the industrial equipment, and generate alarms and notifications when malfunctions are detected. As an example, a process control system may provide redundant servo controllers to ensure continued control of critical, high availability subsystems in the case of a failure in a servo system. Failures may include malfunctioning servo coils, field cables, drive circuits, or other servo control components.
When a failure occurs, the process control system may sense the failure in one of the two circuits providing redundant control of the servo system, isolate the failed circuit, and switch control of the servo system to the other control circuit of the redundant pair automatically. Central process controllers and/or local process controllers may provide the failure sensing and control switchover/failover functionality.